﻿//
// Copyright (c) 2011 Canyala Innovation AB
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of this software and 
// associated documentation files (the "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 
// copies of the Software, and to permit persons to whom the Software is furnished to do so, 
// subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT 
// NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, 
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH 
// THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 
//

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Canyala.Lagoon.Functional
{
    /// <summary>
    /// Generic equality comparer implementation which is returned by the 
    /// Equality.With() static (<see cref="Equality"/>) method to be used with linq expressions where
    /// you need to supply an IEqualityComparer.
    /// </summary>
    /// <typeparam name="T">Type of objects being compared.</typeparam>
    internal class GenericEqualityComparer<T> : EqualityComparer<T> {
        internal GenericEqualityComparer(Func<T, T, bool> equalsFunc) {
            _Equals = equalsFunc;
        }

        internal GenericEqualityComparer(Func<T, T, bool> equalsFunc, Func<T, int> hashcodeFunc) {
            _Equals = equalsFunc;
            _Hashcode = hashcodeFunc;
        }

        protected Func<T, T, bool> _Equals = (x,y) => x.Equals(y);
        protected Func<T, int> _Hashcode = x => x.GetHashCode();

        public override bool Equals(T x, T y) {
            return _Equals(x, y);
        }

        public override int GetHashCode(T obj) {
            return _Hashcode(obj);
        }
    }
}
